Knee replacement surgery — also known as knee arthroplasty (ARTH-row-plas-tee) — can help relieve pain and restore function in severely diseased knee joints. During knee replacement, a surgeon cuts away damaged bone and cartilage from your thighbone, shinbone and kneecap and replaces it with an artificial joint made of metal alloys, high-grade plastics and polymers.

The first artificial knees were little more than crude hinges. Now, you and your doctor can choose from a wide variety of designs that take into account your age, weight, activity level and overall health. Most knee replacement joints attempt to replicate your knee's natural ability to roll and glide as it bends.

The most common reason for knee replacement surgery is to repair joint damage caused by osteoarthritis or rheumatoid arthritis. People who need knee replacement surgery usually have problems walking, climbing stairs, and getting in and out of chairs. They may also experience moderate or severe knee pain at rest.

As with any surgery, knee replacement surgery carries risks, including:

Infection

Blood clots in the leg vein or lungs

Heart attack

Stroke

Nerve damage

Signs of infection

Although the risk of infection is low, notify your doctor immediately if you notice:

Fever greater than 100 F (37.8 C)

Shaking chills

Drainage from the surgical site

Increasing redness, tenderness, swelling and pain in the knee

An infected knee replacement usually requires surgery to remove the artificial parts and antibiotics to kill the bacteria. After the infection is cleared, another surgery is performed to install a new knee. Your chances of a good or excellent outcome that reduces pain and improves function decline with each additional surgery.

Artificial knees can wear out

Another risk of knee replacement surgery is failure of the artificial joint. Subjected to daily stress, even the strongest metal and plastic parts eventually wear out. You're at a greater risk of joint failure if you put more stress on the joint with high-impact activities or excessive weight.

An orthopedic surgeon performs knee replacement procedures. Before the procedure, the surgeon takes your medical history and performs a physical examination to assess your knee's range of motion, stability and strength. X-rays can help determine the extent of knee damage.

Knee replacement surgery requires anesthesia to make you comfortable during surgery. Your input and personal preference help the team decide whether to use general anesthesia, which renders you unconscious during the operation, or spinal or epidural anesthesia, during which you are awake but can't feel any pain from your waist down.

Your doctor or anesthesiologist may advise you to stop taking certain medications and dietary supplements before your surgery. You'll likely be instructed not to eat anything after midnight before your surgery.

Plan ahead for your recovery after surgery

For several weeks after the procedure, you may need the assistance of crutches or a walker. Make advance arrangements for transportation home from the hospital and help with everyday tasks such as cooking, bathing and doing laundry. If you live alone, your surgeon's staff can suggest a temporary caretaker.

To make your home safer and easier to navigate during recovery, consider making the following improvements:

Create a total living space on one floor since climbing stairs can be difficult.

Install safety bars or a secure handrail in your shower or bath.

Secure handrails along your stairways.

Obtain a stable chair with a firm seat cushion and back, and a footstool to elevate your leg.

Arrange for a toilet-seat riser with arms if you have a low toilet.

Try a stable bench or chair for your shower.

Remove all loose carpets and cords.

During the procedure, your knee is in a bent position so that all surfaces of the joint are fully exposed. After making an incision about 6 to 10 inches (15 to 25 centimeters) in length, your surgeon moves aside your kneecap and cuts away the damaged joint surfaces.

After the joint surfaces are prepared, the surgeon inserts and attaches the pieces of the artificial joint. Before closing the incision, he or she bends and rotates your knee, testing and balancing it to ensure that it functions properly. Expect knee replacement surgery to last about two hours.

After knee replacement surgery

After surgery, you're wheeled to a recovery room for one to two hours. You're then moved to your hospital room, where you typically stay for a couple of days before going home. You may feel some pain, but medications prescribed by your doctor should help control it.

During the hospital stay, you're encouraged to move your foot and ankle, which increases blood flow to your leg muscles and helps prevent swelling and blood clots. You may need to receive blood thinners and wear support hose or compression boots to further protect against swelling and clotting.

The day after surgery, a physical therapist shows you how to exercise your new knee. During the first few weeks after surgery, you're more likely to experience a good recovery if you follow all of your surgeon's instructions concerning wound care, diet and exercise. Your physical activity program needs to include:

A graduated walking program — first indoors, then outdoors — to gradually increase your mobility

Slowly resuming other normal household activities, including walking up and down stairs

Knee-strengthening exercises you learned from the hospital physical therapist, performed several times a day

Most people who have a knee replacement experience significant pain relief, improved mobility and a better overall quality of life. Talk with your doctor about what you can expect from knee replacement surgery.

Four to six weeks after knee replacement surgery, you generally can resume most normal daily activities such as shopping and light housekeeping. Driving is also possible at around four weeks if you can bend your knee far enough to sit in a car and you have enough muscle control to properly operate the brakes and accelerator.

After you've recovered, you can enjoy a variety of low-impact activities, such as walking, swimming, golfing or biking. But you should avoid higher impact activities — such as jogging, skiing, tennis, and sports that involve contact or jumping. Talk to your doctor about your limitations.

Experience and expertise. Mayo Clinic surgeons perform more than 2,000 knee replacement surgeries annually. You are cared for by a team that specializes in joint replacement surgery and rehabilitation.

Long-term follow-up. Mayo Clinic tracks the performance of joint replacements over decades, and contacts you on a periodic basis to check on the status of your joint replacement.

Learning from experience. Mayo's Joint Replacement Database contains information on every joint replacement surgery performed at Mayo Clinic. The database helps Mayo Clinic doctors determine which surgical technique and prosthesis type will be the most effective for you. The database has also led doctors to many improvements in surgical techniques and prosthesis designs.

Continuous improvement. Mayo Clinic physicians have published extensively on improving knee replacement care, including such topics as new materials, minimally invasive knee replacement, improvements in pain management after surgery and others.

Cutting-edge medicine. Mayo Clinic's laboratories for Biomechanics and Motion Analysis are involved with developing, modifying and patenting new prosthesis designs, ensuring you'll have access to the latest technology in your new joint.

Mayo Clinic in Rochester, Minn., and Mayo Clinic in Scottsdale, Ariz., are ranked among the Best Hospitals for orthopedics by U.S. News & World Report. Mayo Clinic in Jacksonville, Fla., is ranked high performing for orthopedics by U.S. News & World Report.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.

If the cartilage in just one of the knee's sections becomes damaged, Mayo Clinic surgeons can sometimes replace just the damaged section instead of the whole knee joint. Recovery is easier than with total knee replacement, but the results may not last as long, because arthritis could develop in other areas of the knee.

Minimally invasive surgery

Minimally invasive techniques allow surgeons to replace a knee using smaller incisions. This usually results in less pain and a quicker recovery. But minimally invasive knee replacement requires special surgical training, and it may not work for everyone. Your orthopedic surgeon will determine whether you're a good candidate for the minimally invasive approach.

Robotic assistance

Some Mayo Clinic surgeons use a computer-guided robotic arm during knee replacement surgeries. This device helps the surgeon remove as little bone as possible and precisely align the artificial joint to the bone.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

Mayo Clinic physicians are continually trying to improve the surgical process and results of knee replacement. Research related to knee replacement has included pain management strategies, revision surgeries and advances in minimally invasive knee replacements. In addition, some orthopedic surgeons at Mayo Clinic are involved in artificial knee joint design in the laboratories for Biomechanics and Motion Analysis, where they evaluate better, longer lasting materials and designs to improve care and outcomes.

Publications

See a list of publications by Mayo Clinic doctors on knee replacement on PubMed, a service of the National Library of Medicine.

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